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

int max(int a, int b) {
    return a > b ? a : b;
}

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

int solution(int* height, int n) {
    int totalWater = 0;
    
    for (int i = 0; i < n; i++) {
        // Find max height on left
        int maxLeft = 0;
        for (int j = 0; j < i; j++) {
            maxLeft = max(maxLeft, height[j]);
        }
        
        // Find max height on right
        int maxRight = 0;
        for (int j = i + 1; j < n; j++) {
            maxRight = max(maxRight, height[j]);
        }
        
        // Water trapped at position i
        int waterLevel = min(maxLeft, maxRight);
        if (waterLevel > height[i]) {
            totalWater += waterLevel - height[i];
        }
    }
    
    return totalWater;
}

int main() {
    char line[1000];
    fgets(line, sizeof(line), stdin);
    
    // Parse array - simple parsing for [1,2,3] format
    int height[1000];
    int n = 0;
    char* token = strtok(line, "[,]");
    while (token != NULL) {
        height[n++] = atoi(token);
        token = strtok(NULL, "[,]");
    }
    
    int result = solution(height, n);
    printf("%d\n", result);
    
    return 0;
}