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

double maxSum(FILE* f);

int main() {
    FILE* in = fopen("input.txt", "r");
    if (in == NULL) {
        perror("Could not open input file");
        return (-1);
    }

    double s = maxSum(in);
    fclose(in);

    FILE* out = fopen("output.txt", "w");
    if (in == NULL) {
        perror("Could not open output file");
        return (-1);
    }

    fprintf(out, "%f\n", s);
    fclose(out);
    return 0;
}

double maxSum(FILE* f) {
    double s = -1e+30;      // -infinity
    double s1 = -1e+30;
    double a;
    while (fscanf(f, "%lf", &a) == 1) {
        if (s1 < 0.) {
            s1 = a;
        } else {
            s1 += a;
        }
        if (s < s1)
            s = s1;
    }
    return s;
}