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

struct BinaryTreeNode{
char value;
struct BinaryTreeNode *lchild, *rchild;
};

// 输入值依次是:a、b、#、#、c、#、#
struct BinaryTreeNode *creatBiTree() {
struct BinaryTreeNode *node;
char data;
std::cin>>data;
if (data == '#') {
node = NULL;
} else {
node = (struct BinaryTreeNode *)malloc(sizeof(struct BinaryTreeNode *));
node->value = data;
node->lchild = creatBiTree();
node->rchild = creatBiTree();
};
return node;
}

struct BinaryTreeNode * searchNode(struct BinaryTreeNode *node) {
struct BinaryTreeNode * endNode = NULL;
if (node == NULL) {
return NULL;
}
if (node->value == 'c') {
endNode = node;
} else {
if (endNode == NULL) {
endNode = searchNode(node->lchild);
}
if (endNode == NULL) {
endNode = searchNode(node->rchild);
}
}
return endNode;
}


int main(int argc, const char * argv[]) {
struct BinaryTreeNode *rootNode = creatBiTree();
struct BinaryTreeNode *endNode = searchNode(rootNode);

printf("%d", endNode->value);
return 0;
}