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

int min(int a, int b) {
    return a < b ? a : b;
}

int solution(int* tickets, int ticketsSize, int k) {
    int time = 0;
    int targetTickets = tickets[k];
    
    for (int i = 0; i < ticketsSize; i++) {
        if (i < k) {
            time += min(tickets[i], targetTickets);
        } else if (i == k) {
            time += targetTickets;
        } else {
            time += min(tickets[i], targetTickets - 1);
        }
    }
    
    return time;
}

void parseArray(const char* str, int* arr, int* size) {
    *size = 0;
    const char* p = str;
    while (*p && *p != '[') p++;
    if (*p == '[') p++;
    while (*p && *p != ']') {
        while (*p == ' ' || *p == ',') p++;
        if (*p == ']' || *p == '\0') break;
        arr[(*size)++] = (int)strtol(p, (char**)&p, 10);
    }
}

int main() {
    char line[1000];
    fgets(line, sizeof(line), stdin);
    
    int tickets[100];
    int size = 0;
    char* token = strtok(line + 1, ",]");
    while (token != NULL) {
        tickets[size++] = atoi(token);
        token = strtok(NULL, ",]");
    }
    
    int k;
    scanf("%d", &k);
    
    int result = solution(tickets, size, k);
    printf("%d\n", result);
    
    return 0;
}