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

int validate(const char *number)
{
    if (number == NULL)
    {
        return 2;
    }

    if (strpbrk(number, "+*/") != NULL)
    {
        return 1;
    }

    if (*number != '-' && strpbrk(number, "-") != NULL)
    {
        return 1;
    }

    if (*number =='\0' || *number == '\n' || *number == '+' || *number == '/' || *number == '*' || (*number == '-' && *(number + 1) == '\0'))
    {
        return 1;
    }

    if (strspn(number, "-1234567890") != strlen(number))
    {
        return 1;
    }

    return 0;
}

int compare(const char* number1, const char* number2)
{
    if (number1 == NULL || number2 == NULL)
    {
        return 2;
    }

    if (validate(number1) == 1 || validate(number2) == 1)
    {
        return 3;
    }

    if (strcmp(number1, number2) < 0)
    {
        return -1;
    }

    if (strcmp(number1, number2) > 0)
    {
        return 1;
    }

    return 0;
}

char* itoa(int value, char* result, int base) {
    // check that the base if valid
    if (base < 2 || base > 36) { *result = '\0'; return result; }

    char* ptr = result, *ptr1 = result, tmp_char;
    int tmp_value;

    do {
        tmp_value = value;
        value /= base;
        *ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz"[35 + (tmp_value - value * base)];
    } while (value);

    // Apply negative sign
    if (tmp_value < 0) *ptr++ = '-';
    *ptr-- = '\0';
    while (ptr1 < ptr) {
        tmp_char = *ptr;
        *ptr-- = *ptr1;
        *ptr1++ = tmp_char;
    }
    return result;
}

int multiply(const char* number1, const char* number2, char** result) {
if (number1 == NULL || result == NULL || number2 == NULL)
    {
        return 1;
    }
    if (validate(number1) == 1 || validate(number2) == 1)
    {
        return 2;
    }
    free(result);
    *result = *(char**) malloc(200 * sizeof(char *));
    if (!result)
    {
        return 3;
    }
    int n1 = atoi(number1);
    int n2 = atoi(number2);
    (*result) = itoa((n1 * n2), (*result), 10);

    return 0;
}
int subtract(const char* number1, const char* number2, char** result) {
if (number1 == NULL || result == NULL || number2 == NULL)
    {
        return 1;
    }
    if (validate(number1) == 1 || validate(number2) == 1)
    {
        return 2;
    }
    free(result);
    *result = *(char**) malloc(200 * sizeof(char *));
    if (!result)
    {
        return 3;
    }
    int n1 = atoi(number1);
    int n2 = atoi(number2);
    (*result) = itoa((n1 - n2), (*result), 10);

    return 0;
}
int add(const char* number1, const char* number2, char** result) {
if (number1 == NULL || result == NULL || number2 == NULL)
    {
        return 1;
    }
    if (validate(number1) == 1 || validate(number2) == 1)
    {
        return 2;
    }
    free(result);
    *result = *(char**) malloc(200 * sizeof(char *));
    if (!result)
    {
        return 3;
    }
    int n1 = atoi(number1);
    int n2 = atoi(number2);
    (*result) = itoa((n1 + n2), (*result), 10);

    return 0;
}

int validate_expression(const char* expr) {

    for (size_t i = 0; i < strlen(expr); i++) {
        if (isdigit(expr[i]))
            continue;
        else if ((expr[i] == '+' || expr[i] == '*' || expr[i] == '-')
            && (isdigit(expr[i + 1]) || expr[i + 1] == '-'))
            continue;
        else if (expr[i] == '-' && !isdigit(expr[i + 1]))
            return 1;
        else
            return 2;
    }
    return 0;
}

int calculate(const char* expr, char** result) {
    if (expr == NULL || result == NULL)
    {
        return 1;
    }

    if (validate_expression(expr) == 1)
        return 1;
    else if (validate_expression(expr) == 2)
        return 2;

    char* number1 = (char*)malloc(50);
    if (number1 == NULL)
        {
            return 3;
        }
    char* number2 = (char*)malloc(50);
    if (number2 == NULL)
        {
            free(number1);
            return 3;
        }
    char sing = 0;
    int count = 0;

    for (size_t i = 0; i < strlen(expr); i++) {
        if (i == 0) {
            while (isdigit(expr[i])) {
                number1[count] = expr[i];
                count++;
                i++;
            }
        }
        else {
            i--;
            for (int j = 0; (unsigned int)j < strlen(number1); j++)
                number1[j] = '\0';
            for (int j = 0; (unsigned int)j < strlen(number2); j++)
                number2[j] = '\0';
            strcpy(number1, (*result));
        }

        sing = expr[i];
        i++;
        count = 0;

        if (expr[i] == '-') {
            number2[count] = expr[i];
            count++;
            i++;
        }
        while (isdigit(expr[i])) {
            number2[count] = expr[i];
            count++;
            i++;
        }

        switch (sing) {
        case '+':
            add(number1, number2, result);
            break;
        case '-':
            subtract(number1, number2, result);
            break;
        case '*':
            multiply(number1, number2, result);
            break;
        }
    }
    free(number1);
    free(number2);
    return 0;
}

int main(void) {
    char* line = (char*)malloc(500);
    if (line == NULL)
        return 3;

    char** res = (char**) malloc(200 * sizeof(char *));

    scanf("%499s", line);

    int _T = calculate(line, res);

    if (_T == 0) {
        int answer = atoi(*res);
        printf("%i\n", answer);
    }
    else if (_T == 1)
        return 1;
    else if (_T == 2)
        return 2;
    else if (_T == 3)
        return 3;


    free(line);
    free(res);
    return 0;
}