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

#define DONT_KNOW "I_dont_know"

void printIDontKnow()
{
    printf("%s", DONT_KNOW);
    exit(0);
}

int examA_q2(char **arr, int n, int m);

//Do not change these functions
void free_string_arr(char **arr, int n)
{
    for (int i = 0; i < n; ++i)
    {
        free(arr[i]);
    }
    free(arr);
}

bool read_string(char **s)
{
    int len;
    if (scanf("%d", &len) != 1)
    {
        return false;
    }
    *s = malloc((len + 1) * sizeof(char));
    if (!*s)
    {
        return false;
    }
    if (scanf("%s", *s) != 1)
    {
        free(*s);
        return false;
    }
    return true;
}

int main(void)
{
    // uncomment next line if you don't know the answer
    // printIDontKnow();

    int n;
    if (scanf("%d", &n) != 1)
        return 1;
    char **arr = malloc(sizeof(char *) * n);
    if (!arr)
        return 1;
    for (int i = 0; i < n; i++)
    {
        if (!read_string(arr + i))
        {
            free_string_arr(arr, i);
            return 1;
        }
    }
    int m;
    if (scanf("%d", &m) != 1)
    {
        free_string_arr(arr, n);
        return 1;
    }
    printf("%d", examA_q2(arr, n, m));
    free_string_arr(arr, n);
    return 0;
}

int getLineLength(char **arr, int startWord, int endWord)
{
    int len = 0;
    for (int i = startWord; i <= endWord; i++)
    {
        len += strlen(arr[i]);
    }

    return len;
}

int getWordMin(char **arr, int n)
{
    int min = strlen(arr[0]);

    for (int i = 1; i < n; i++)
    {
        int len = strlen(arr[i]);
        if (len < min)
        {
            min = len;
        }
    }

    return min;
}

#define IS_DIGIT(c) (c >= '0' && c <= '9')


int examA_q2(char **arr, int n, int m)
{
    // if there are more lines then words, each word can be on a separate line.
    if (m >= n)
    {
        return getWordMin(arr, n);
    }
    int absoluteMinimum = -1;

    // I coun't think fast and finish this in time, so:
    // Take the full line and start removing words from the end.
    // if its posible each word on a new line.
    // if there are no more lines, we need to check the lest lines and figure
    // out if moving the next word down will cost more then moving the last word
    // up and putting the new word in a separte line.
    // each time we do this we will save the absoluteMinimum and thats what we
    // will get at the end.

    // return
    return absoluteMinimum;
}