#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
const int maxlen = 10000;
char a[maxlen];
//Accepted 1013 0MS 244K 630 B C++ Achiberx
int get(int a) {
int s=0;
while(a) {
s += a%10;
a /= 10;
}
if(s>9) {
return get(s);
}
else {
return s;
}
}
int work() {
int len = strlen(a);
int s = 0;
for(int i = 0; i < len; i++) {
int tmp = a[i] - '0';
s += tmp;
}
return get(s);
}
int main() {
while(scanf("%s", a) != EOF) {
if(a[0] == '0') break;
int res = work();
printf("%d\n", res);
}
return 0;
}
简单的水题,注意一下,正整数可能会很多远远超过int。。。