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

int compare(const void *a, const void *b) {
    return (*(int*)a - *(int*)b);
}

long long sumRange(int start, int end) {
    // Sum of consecutive integers from start to end (inclusive)
    long long count = end - start + 1;
    return count * (start + end) / 2;
}

long long solution(int* nums, int numsSize, int k) {
    // Filter positive numbers, sort and remove duplicates
    int positiveNums[10000];
    int positiveSize = 0;
    
    for (int i = 0; i < numsSize; i++) {
        if (nums[i] > 0) {
            positiveNums[positiveSize++] = nums[i];
        }
    }
    
    qsort(positiveNums, positiveSize, sizeof(int), compare);
    
    // Remove duplicates
    int uniqueSize = 0;
    for (int i = 0; i < positiveSize; i++) {
        if (i == 0 || positiveNums[i] != positiveNums[i-1]) {
            positiveNums[uniqueSize++] = positiveNums[i];
        }
    }
    
    long long missingSum = 0;
    int missingCount = 0;
    int current = 1;
    
    for (int i = 0; i < uniqueSize; i++) {
        if (missingCount >= k) {
            break;
        }
        
        if (current < positiveNums[i]) {
            // There's a gap, fill it with missing numbers
            int gapSize = positiveNums[i] - current;
            int take = (gapSize < k - missingCount) ? gapSize : k - missingCount;
            missingSum += sumRange(current, current + take - 1);
            missingCount += take;
        }
        
        current = (current > positiveNums[i] + 1) ? current : positiveNums[i] + 1;
    }
    
    // If we still need more numbers, add consecutive numbers after the largest
    if (missingCount < k) {
        int remaining = k - missingCount;
        missingSum += sumRange(current, current + remaining - 1);
    }
    
    return missingSum;
}

int main() {
    char line[100000];
    fgets(line, sizeof(line), stdin);
    
    int nums[10000];
    int numsSize = 0;
    char* token = strtok(line + 1, ",]");
    while (token != NULL) {
        nums[numsSize++] = atoi(token);
        token = strtok(NULL, ",]");
    }
    
    int k;
    scanf("%d", &k);
    
    long long result = solution(nums, numsSize, k);
    printf("%lld\n", result);
    
    return 0;
}