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

char* solution(int N) {
    static const int size = (int)('z' - 'a');
    const int interval = (int)ceil((double)N / (double)size);

    char* str = (char*)malloc((N + 1) * sizeof(char));
    str[N] = '\0';
    int count = 0;
    char offset = 0;
    for (int i = 0; i < N; ++i) {
        str[i] = 'a' + offset;
        if (++count >= interval) {
            count = 0;
            ++offset;
        }
    }
    return str;
}

int main() {
    {
        char* str = solution(3);
        printf("%s\n", str);
        free(str);
    }
    return 0;
}