include <stdio.h>

int main() {

int n;
scanf("%d", &n);

if (n >= 100 && n <= 999) {
    int reversedNumber = 0;

    reversedNumber += (n % 10) * 100;
    n /= 10;
    reversedNumber += (n % 10) * 10;
    n /= 10;
    reversedNumber += (n % 10);

    printf("%d\n", reversedNumber);
} else {
    printf("None\n");
}

return 0;

}