#include <stdio.h>
//#define MAX_SIZE 20

int main(void){
    int input_data[20][20];
    int input_box[20][20];
    int data = 0;

    //first input
    int x = 0;
    int y = 0;
    int num_area = 0;

    //selected area data
    int x1;    //x coordinate of left top
    int y1;    //y coordinate of lef top
    int x2;    //x coordinate of right bottom
    int y2;    //x coordinate of right bottom

    //loop variable
    int i;  //for x axis
    int j;  //for y axis
    int k;  //for collecting data

    scanf("%d %d %d", &x, &y, &num_area);

    //0 clear arrays
    for(j = 0; j < y; j++){
        for(i = 0; i < x; i++){
            input_data[i][j] = 0;
            input_box[i][j]  = 0;

            //store data into array
            scanf("%d", &input_data[i][j]);
        }
    }

    //store data, * number of selected area
    for(k = 0; k < num_area; k++){

        //get the coordinates of the selected area
        scanf("%d %d %d %d", &x1, &y1, &x2, &y2);

        //add the data of selected area
        for(j = y1-1; j <= y2-1; j++){
            for(i = x1-1; i <= x2-1; i++){
                data += input_data[i][j];

                //0 clear the used array so than not to add again
                input_data[i][j] = 0;
            }
        }
    }

    printf("%d\n", data);

    return 0;
}