Loop runs till square root
for ( lli i = 1 ; i <= sqrt ( N ) + 1 ; i ++ ) { if ( N % i == 0 ) { if ( i == N / i ) { if ( i % 2 == 0 ) ev_count += 1 ; else od_count += 1 ; } else { if ( i % 2 == 0 ) ev_count += 1 ; else od_count += 1 ; if ( ( N / i ) % 2 == 0 ) ev_count += 1 ; else od_count += 1 ; } } }