#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <time.h>
#include <string.h>
#include <math.h>

extern float dot_product(int n, const float *x, const float *y);

int main() {
    int n;
    scanf("%d", &n);
    float *x = calloc(n, sizeof(float));
    float *y = calloc(n, sizeof(float));
    for (int i = 0; i < n; i++) {
        scanf("%f", &(x[i]));
    }
    for (int i = 0; i < n; i++) {
        scanf("%f", &(y[i]));
    }
    float res = dot_product(n, x, y);
    printf("%f\n", res);
    free(x);
    free(y);
    return 0;
}