class Multiply {
    //@ requires n>0;
    //@ ensures \result == m*n;
    int multiply(int m, int n) {
	int result = 0;
	int i = 0;
	//@ loop_invariant result == m*i && i >= 0 && i <= n && n>0;
	while (i < n) {
	    result = add(result,m);
	    i = i + 1;
	}
	return result;
    }

    //@ ensures \result == n+m;
    int add(int n, int m) {
	return n+m;
    }
}