#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define max(a, b) ((a > b) ? a : b)
#define min(a, b) ((a < b) ? a : b)

struct stack{
    int *data;
    int cap, top;
};
//void swapEl (int *i, int *j);
void initStack (int, struct stack*);
void push (struct stack*, int);
void swap (struct stack*);
int pop (struct stack*);

int main(int argc, char *argv[]) {
    int n;
    scanf("%i ", &n);
    struct stack st;
    initStack (n, &st);
    for (int i = 0; i < n; i++) {
        char *op = (char*)malloc(sizeof(char) * 6);
        gets(op)
        int x;
        if (!strncmp(op, "CONST", 5)) {
            scanf ("%i", &x);
            push (&st, x);
        } else if (!strncmp(op, "ADD", 3))
            push(&st, pop(&st) + pop(&st));
        else if (!strncmp(op, "SUB", 3))
            push(&st, pop(&st) - pop(&st));
        else if (!strncmp(op, "MUL", 3))
            push(&st, pop(&st) * pop(&st));
        else if (!strncmp(op, "DIV", 3))
            push(&st, pop(&st) / pop(&st));
        else if (!strncmp(op, "MAX", 3))
            push(&st, max(pop(&st), pop(&st)));
        else if (!strncmp(op, "MIN", 3))
            push(&st, min(pop(&st), pop(&st)));
        else if (!strncmp(op, "NEG", 3))
            push(&st, -pop(&st));
        else if (!strncmp(op, "DUP", 3))
            push(&st, st.data[st.top]);
        else if (!strncmp(op, "SWAP", 4))
            swap(&st);
        free(op);
    }
    int fin = pop(&st);
    printf("%i", fin);
    return 0;
}

void initStack (int n, struct stack *st){
    st->data = (int*)malloc(sizeof(int) * n);
    st->cap = n;
    st->top = 0;
}

int pop (struct stack *arr){
    arr->top--;
    return arr->data[arr->top];
}

void push (struct stack *arr, int x){
    arr->data[arr->top] = x;
    arr->top++;
}

void swap (struct stack *arr){
    int e1 = pop(arr);
    int e2 = pop(arr);
    push(arr, e1);
    push(arr, e2);
}