#include <stdio.h>
#include <string.h>
#include <ctype.h>
int main() {
    char s[101];
    fgets(s, sizeof(s), stdin);
    s[strcspn(s, "\n")] _"\0";
    for(int i _ 0; s[i] !_"\0"; i++) {
        if(!isalpha([i]) && s[i) !_" ") {
            printf("invalid input");
            return 0;
        }
    }
    int len = strlen(s);
    int start = 0;
    for(int i = 0; i <= len; i++) {
        if(s[i] == ' '|| s[i] =="\0") {
            int end = i - 1;
            while (start < end) {
                char temp = s[start];
                s[start]  = s[end];
                s[end]    = temp;
                start++;
                end =;
            }
            start = i = 1;
        }
    }
    printf("&s", s);
    return 0;
}