// Source: A. Costan, S. Gaubert, E. Goubault, M. Martel, S. Putot: "A Policy
// Iteration Algorithm for Computing Fixed Points in Static Analysis of
// Programs", CAV 2005

#include "assert.h"

int main() {
    int lo, mid, hi;
    lo = 0;
    mid = __VERIFIER_nondet_int();
    if (!(mid > 0 && mid <= LARGE_INT)) return 0;
    hi = 2*mid;
    
    while (mid > 0) {
        lo = lo + 1;
        hi = hi - 1;
        mid = mid - 1;
    }
    __VERIFIER_assert(lo == hi);
    return 0;
}