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int main() { int n; int t; int c; int p; c = 0; n = 2; while (n < 5000) { t = 2; p = 1; while (t*t <= n) { if (n % t == 0) p = 0; t++; } n++; if (p) c++; } if (c != 669) return 1; return 0; }