#include <stdio.h>

int main(){
    int P1, P2, N, R, M = 0, c = 0, i;

    scanf("%d%d", &P1, &P2);
    scanf("%d", &N);
    for (i = 0; i < N; i++) {
    	scanf("%d", &R);
    	if (R == M) {
    		c++;
    	}
    	else {
    		M = R;
    	}
    }
    printf("%d", c*(P1 + P2));
}