#include <stdio.h> int main() { int n; scanf("%d", &n); int sum = 0; while(n / 10) { while(n) { sum += n % 10; n /= 10; } n = sum; sum = 0; } printf("%d", n); return 0; }
#include <stdio.h> int main() { int n; scanf("%d", &n); int sum = 0; while(n / 10) { while(n) { sum += n % 10; n /= 10; } n = sum; sum = 0; } printf("%d", n); return 0; }