#includeint main() { int i, j; long long sum = 0, jieCheng; for (i = 1; i <= 20; i++) { jieCheng = 1; for (j = 1; j <= i; j++) { jieCheng *= j; } sum += jieCheng; } printf("%lld", sum); return 0; }

#includeint main() { int i, j; long long sum = 0, jieCheng; for (i = 1; i <= 20; i++) { jieCheng = 1; for (j = 1; j <= i; j++) { jieCheng *= j; } sum += jieCheng; } printf("%lld", sum); return 0; }