int minValue(Node* root) {
if(root==NULL) return -1;
while(root->left!=NULL)
root=root->left;
return root->data;
}
int minValue(Node* root) {
if(root==NULL)
return -1;
int t = root->data;
if(root->left!=NULL)
t = minValue(root->left);
return t;
}