4K2K! の巻

#include <stdio.h>

main()
{
    int ch, ch2;

    while((ch = getchar()) != EOF){
        if(ch != '4'){
            putchar(ch);
            continue;
        }

        if ((ch2 = getchar()) == EOF){
            putchar(ch);
            break;
        }

        if (ch2 == '4'){
            putchar(ch);
            ungetc('4', stdin);
            continue;
        }

        if(ch2 == 'k'){
            putchar('k');
        }else if(ch2 == 'K'){
            putchar('K');
        }else{
            putchar(ch);
            putchar(ch2);
        }
    }
}

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