#include "stdio.h"
#include "stdlib.h"

char* string();

int main() {

    printf("%s", string());

    return 0;
}

char* string() {
    char input[128];
    printf("enter a word: ");
    scanf("%s", input);
    int counter = 0;
    char temp[128];
    int i = 0;
    while (i < input[i]) {
        if ('a' <= input[i] && input[i] <= 'z') {
            temp[counter] = input[i];
            counter++;
        }
        else if ('A' <= input[i] && input[i] <= 'Z') {
            temp[counter] = input[i]+32;
            counter++;
        }
        else if (input[i] == '.' || input[i] == ',' || input[i] == '?' || input[i] == '!') {
            temp[counter] = input[i];
            counter++;
        }
        i++;
    }
    char* output = (char*)malloc(counter * sizeof(char));
    i = 0;
    while (i < counter) {
        *(output + i) = temp[i];
        i++;
    }
    *(output + counter) = '\0';


    return output;
}