// editor4#include <stdio.h>
#include <string.h>

int main() {
    char str[10005]; // max length as per constraints
    char stack[10005];
    int top = -1;

    if (fgets(str, sizeof(str), stdin) == NULL) {
        printf("Invalid input\n");
        return 0;
    }

    // Remove newline character if present
    int len = strlen(str);
    if (str[len-1] == '\n') {
        str[len-1] = '\0';
        len--;
    }

    // Validate characters and push to stack
    for (int i = 0; i < len; i++) {
        if (str[i] < 32 || str[i] > 126) {
            printf("Invalid input\n");
            return 0;
        }
        stack[++top] = str[i];  // push operation
    }

    // Pop and print reversed string
    while (top >= 0) {
        printf("%c", stack[top--]);
    }
    printf("\n");

    return 0;
}