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

typedef struct stack{
    int *tab;
    int top;
    int maxsize;
}stack;
void push(stack* stos, int el){
    stos->top++;
    stos->tab[stos->top]=el;
}
int pop(stack* stos){
    int res = stos->tab[stos->top];
    stos->top--;
    return res;
}
void add(stack *stos){
    int a = pop(stos);
    int b = pop(stos);
    push(stos, b+a);
}
void subtract(stack *stos){
    int a = pop(stos);
    int b = pop(stos);
    push(stos, b-a);
}
void multiply(stack *stos){
    int a = pop(stos);
    int b = pop(stos);
    push(stos, b*a);
}
void divide(stack *stos){
    int a = pop(stos);
    int b = pop(stos);
    push(stos, b/a);
}
int calconp(stack *stos, int n, int k){
    char *what;
    what = malloc((k+1)*sizeof(char));
    int i=n;
    while(i>0 || stos->top>0){
        scanf("%s", what);
        if(what[0]=='+') add(stos);
        if(what[0]=='-') subtract(stos);
        if(what[0]=='*') multiply(stos);
        if(what[0]=='/') divide(stos);
        if(what[0]>=48 && what[0]<58){
            int number = 0;
            int j=0;
            while(j<k && what[j]!='\0'){
                number = 10*number+what[j]-48;
                j++;
            }
            push(stos,number);
            i--;
        }
    }
    free(what);
    return stos->tab[0];
}



int main(){
    int n, k;
    scanf("%d %d", &n, &k);
    stack *stos=malloc(2*sizeof(int)+sizeof(int*));
    stos->tab=malloc(n*sizeof(int));
    stos->top=-1;
    stos->maxsize=n;
    int res = calconp(stos,n,k);
    printf("%d", res);
    free(stos->tab);
    free(stos);
    return 0;
}