#pragma TASS input 
int N_BOUND;
#pragma TASS input {n>=0 && n<=N_BOUND}
int n;
#pragma TASS output 
int out;

void main() {
  int i;
  int s=0;
  
  for (i=0; i<n; i=i+1) s=s+i;
  out=s;
  #pragma TASS assert s==(n*(n-1))/2; /* doublely want (n*(n-1))/2 */
}
