import java.util.*;
public class mult
{
 public static void main(String args[])
{
 int i,j,k,m,n,m1,n1;
 Scanner s= new Scanner(System.in);
 System.out.println("enter the no.of rows of matrix a");
 m=s.nextInt();
 System.out.println("enter the no.of columns of matrix a");
 n=s.nextInt();
 int a[][]= new int[m][n];

 System.out.println("enter the elmnts of a");
 for(i=0;i<m;i++)
 {for(j=0;j<n;j++)
   a[i][j]=s.nextInt();
  }

  System.out.println("enter the no.of rows of matrix b");
 m1=s.nextInt();
 System.out.println("enter the no.of columns of matrix b");
 n1=s.nextInt();
 int b[][]= new int[m1][n1];
 
  System.out.println("enter the elmnts of b");
  for(i=0;i<m1;i++)
 {for(j=0;j<n1;j++)
   b[i][j]=s.nextInt();
  }
 System.out.println("Matrix a");
 for(i=0;i<m;i++)
{ for(j=0;j<n;j++)
 { System.out.print(" "+a[i][j]);
  }
  System.out.println();
 }
 System.out.println("Matrix b");
 for(i=0;i<m;i++)
{ for(j=0;j<n1;j++)
  {System.out.print(" "+b[i][j]);
  }
  System.out.println();}
  if(n==m1)
{ 
  int c[][]=new int[m][n1];
  for(i=0;i<m;i++)
 { 
   for(j=0;j<n1;j++)
   {
     c[i][j]=0;
   for(k=0;k<n;k++)
  { c[i][j]=c[i][j]+(a[i][k]*b[k][j]);
   }
  }
 }
 System.out.println("resultant matrix");
 for(i=0;i<m;i++)
{ for(j=0;j<n1;j++)
  {System.out.print(" "+c[i][j]);
  }
  System.out.println();
 }

}
else
 System.out.println("not in order for multiplication");
}
}








import java.util.*;
public class trace
{public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
int i,n,n1,j,s=0;
System.out.println("Enter the array size n and n1 ");
n=sc.nextInt();
n1=sc.nextInt();
int[][] a=new int[n][n1];
System.out.println("enter first array elements");
for(i=0;i<n;i++)
{for(j=0;j<n1;j++)
{
    a[i][j]=sc.nextInt();
}   
}

for(i=0;i<n;i++){
    s+=a[i][i];}
System.out.println("sum of trace elements="+s);}}





import java.util.*;
public class palindromes
{
public static void main(String args[])
{
Scanner sc =new Scanner(System.in);
int l,j,f=0,i;
System.out.println("enter the word");
String s=sc.next();
j=s.length();
for(i=0;i<j/2;i++)
{if(s.charAt(i)!=s.charAt(j-1)){
    f=1;
    break;}
    j--;
}
if(f==1)
{System.out.println("not palindrome");}
else
{System.out.println("palindrome");
}}}







import java.util.*;
public class searchcc
{
public static void main(String args[])
{
Scanner sc =new Scanner(System.in);
int l,j,f=0,i;
System.out.println("enter the sentence");
String s=sc.nextLine();
System.out.println("enter the character");
char c;
c=sc.next().charAt(0);
j=s.length();
for(i=0;i<j;i++)
{if(s.charAt(i)==c){
    f=1;
    break;}
}
if(f==1)
{System.out.println("found at position"+i);}
else
{System.out.println("palindromnot found");
}}}












import java.util.*;
public class replace
{
public static void main(String args[])
{
Scanner sc =new Scanner(System.in);
int j;
System.out.println("enter the  setence");
String s=sc.nextLine();
String b;

System.out.println("enter the charactert to be repalced and with what");
char c,d;
c=sc.next().charAt(0);
d=sc.next().charAt(0);
j=s.length();

System.out.println(s.replace(c,d));
b=s.replace(c,d);
    


System.out.println(b);

}}