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

#define MAX_NAME 50

int look = 0;
char name[MAX_NAME+1];
int vars[26] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

void next() {
    look = getchar();
}

// <name> ::= ['_'|<letter>] '_'|<letter>|<number>
char* getName() {
    int i = 0;

    if (look == '_' || isalpha(look))
    while ((look == '_' || isalnum(look)) && i < MAX_NAME) {
        name[i++] = look;
        next();
    }
    name[i] = '\0';

    return name;
}

// <number> ::= [0-9]+
char* getNumber() {
    int i = 0;

    while ((isdigit(look)) && i < MAX_NAME) {
        name[i++] = look;
        next();
    }
    name[i] = '\0';

    return name;
}

void match(char ch) {
    if (look != ch) {
        printf("Invalid symbol %c\n", ch);
        exit(0);
    }

    next();
}

// <expression> ::= <number>+
void expression() {
    char var = name[0];
    match('=');

    if (!isdigit(look)) {
        printf("Not a number\n");
        exit(0);
    }

    vars['z' - tolower(var)] = atoi(getNumber());
}

// print <var>
void print() {
    match(' ');

    if (!isalpha(look)) {
        printf("Not a variable!\n");
        exit(0);
    }

    printf("%d\n", vars['z' - look]);
    next();
}

// <program> ::= <expression> | <print>
void program() {
    getName();

    if (strlen(name) == 1 && isalpha(name[0])) { // expression
        expression();
    } else if (!strcmp(name, "print")) { // print
        print();
    } else {
        printf("Invalid program\n");
        exit(0);
    }
}

int main()
{
    next();

    while (look != '\n' && look != EOF) {
        program();
        match(';');
    }
}