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

int main()
{
	int x,y,z;
	int *p;
	int i = 0;
	int sum = 0;
	
	scanf("%d\n", &x);
	scanf("%d\n", &y);
	scanf("%d\n", &z);
	
	p = (int*)malloc(sizeof(int) * z);
	
	while(i < z){
		scanf("%d\n", p[i]);
		i++;
	}
	i = 0;
	while(i < z){
		if(i+1 != z){
			if(p[i] == p[i + 1]){
			sum += 1;
		}
		}
		i++;
	}
	printf("%d\n", sum * (x + y));
	
	return (0);
}