#include <stdio.h>

int main() {
    char idCardNo[18] = {0};
    int i = 0, sum = 0;
    int temp = 0;
    char checkSum = 0;
    int weigh[17] = {7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2};
    for (i = 0; i < 18; i++) {
        idCardNo[i] = getchar();
    }
    for (i = 0; i < 17; i++) {
        temp = ((idCardNo[i] - '0')*weigh[i]) % 11;
        sum += ((idCardNo[i] - '0')*weigh[i]) % 11;
    }
    checkSum = (12 - (sum % 11)) % 11;
    if (checkSum == 10) {
        checkSum = 'X';
    }
    else {
        checkSum += '0';
    }
    if (checkSum == idCardNo[17]) {
        printf("合法\n");
    }
    else {
        printf("非法，正确校验位是%c", checkSum);
    }
    return 0;
}