Problem:
Score : 100 points

Problem Statement

In the Kingdom of AtCoder, people use a language called Taknese, which uses lowercase English letters.

In Taknese, the plural form of a noun is spelled based on the following rules:

If a noun's singular form does not end with s, append s to the end of the singular form.

If a noun's singular form ends with s, append es to the end of the singular form.

You are given the singular form S of a Taknese noun. Output its plural form.

Constraints

S is a string of length 1 between 1000, inclusive.

S contains only lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

Print the plural form of the given Taknese word.

Sample Input 1

apple

Sample Output 1

apples

apple ends with e, so its plural form is apples.

Sample Input 2

bus

Sample Output 2

buses

bus ends with s, so its plural form is buses.

Sample Input 3

box

Sample Output 3

boxs

Solution in C (GCC 9.2.1) (judge verdict: Wrong Answer)

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

int main(int argc, const char * argv[]) {
    char buf[100] =  "  ";
    char * const word = buf + 2;
        scanf("%90s", word);
        char *tail = word + strlen(word) - 1;
        if (strchr("sox", *tail) != NULL
        ||  strcmp(tail - 1, "sh") == 0
        ||  strcmp(tail - 1, "ch") == 0) {
            strcpy(tail + 1, "es");
        } else if (*tail == 'f') {
            strcpy(tail, "ves");
        } else if (strcmp(tail - 1, "fe") == 0) {
            strcpy(tail - 1, "ves");
        } else if (*tail == 'y' && strchr("aiueo", tail[-1]) == NULL) {
            strcpy(tail, "ies");
        } else {
            strcpy(tail + 1, "s");
        }
        printf("%s\n", word);
}