// This file is part of the SV-Benchmarks collection of verification tasks:
// https://gitlab.com/sosy-lab/benchmarking/sv-benchmarks
//
// SPDX-FileCopyrightText: 2012-2021 The SV-Benchmarks Community
// SPDX-FileCopyrightText: 2012 FBK-ES <https://es.fbk.eu/>
//
// SPDX-License-Identifier: Apache-2.0

extern void abort(void);
extern void __assert_fail(const char *, const char *, unsigned int, const char *) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__noreturn__));
void reach_error() { __assert_fail("0", "sum02-1.c", 3, "reach_error"); }

void __VERIFIER_assert(int cond) {
  if (!(cond)) {
    ERROR: {reach_error();abort();}
  }
  return;
}
extern unsigned int __VERIFIER_nondet_uint();
int main() { 
  unsigned int i, n=__VERIFIER_nondet_uint(), sn=0;
  for(i=0; i<=n; i++) {
    sn = sn + i;
  }
  __VERIFIER_assert(sn==(n*(n+1))/2 || sn == 0);
}