/*
PROOF OF CORRECTNESS:
  DIFF(X,Y): compute X - Y 
*/
#include <stdio.h>

int diff(int x, int y) {
int z, w;

  // PRE: y >= 0
  
  z = x;



  w = y;

  
  
  // INVARIANT:
  
  while ( w > 0 ) {




    z = z - 1;
    





    w = w - 1;




  }
  

  // INVARIANT:                                       and EXIT: 
  


  // POST: z = x - y
  
  return z;
}


int main() {
int x, y;
  scanf("%d %d",&x,&y);
  printf("diff(%d,%d)=%d\n",x,y,diff(x,y));
}