#include<bits/stdc++.h>
 
int max(int a, int b);
 
int lcs( char *X, char *Y, int m, int n )
{
   if (m == 0 || n == 0)
     return 0;
   if (X[m-1] == Y[n-1])
     return 1 + lcs(X, Y, m-1, n-1);
   else
     return max(lcs(X, Y, m, n-1), lcs(X, Y, m-1, n));
}
 
int max(int a, int b)
{
    return (a > b)? a : b;
}
 
int main()
{
  char X[] = "AGGTAB";
  char Y[] = "GXTXAYB";
 
  int m = strlen(X);
  int n = strlen(Y);
 
  printf("Length of LCS is %d\n", lcs( X, Y, m, n ) );
 
  return 0;
}