#include <stdio.h>
#include <string.h>
#include <stdbool.h>

void read_set(char set[]);
bool contains_same_letters(const char set[]);


int main() {
    // reading set 1
    char set1[50];
    read_set(set1);

    // check for same letters
    if (contains_same_letters(set1)) {
        printf("Wrong input.\n");
        return -1;
    }

    return 0;
}

void read_set(char set[]) {
    printf("Enter set 1: ");
    scanf("%s", set);
}

bool contains_same_letters(const char set[]) {
    for (int index = 0, len = (int) strlen(set); index < len - 1; index++) {
        for (int index2 = index + 1; index2 < len; index2++) {
            if (set[index] == set[index2]) {
                return true;
            }
        }
    }
    return false;
}