diff --git a/Codeforces/Codeforces_401_777B.cpp b/Codeforces/Codeforces_401_777B.cpp
new file mode 100644
index 0000000..07e157b
--- /dev/null
+++ b/Codeforces/Codeforces_401_777B.cpp
@@ -0,0 +1,21 @@
+#include<bits/stdc++.h>
+using namespace std;
+int main(){
+int n,j;
+string s,m;
+cin>>n;
+cin>>s>>m;
+sort(s.begin(),s.end());
+sort(m.begin(),m.end());
+j=n-1;
+for(int i=n-1;i>=0;i--){
+    if(s[i]<=m[j])j--;
+}
+cout<<j+1<<"\n";
+j=0;
+for(int i=0;i<n;i++){
+    if(m[i]>s[j])j++;
+}
+cout<<j;
+return 0;
+}
\ No newline at end of file
diff --git a/Codeforces/Codeforces_77_96B.cpp b/Codeforces/Codeforces_77_96B.cpp
new file mode 100644
index 0000000..f4171c2
--- /dev/null
+++ b/Codeforces/Codeforces_77_96B.cpp
@@ -0,0 +1,20 @@
+#include<bits/stdc++.h>
+using namespace std;
+long long  n;
+string s;
+int main()
+{
+   cin>>n;
+   while(1)
+   {
+       s+="47";
+       sort(s.begin(),s.end());
+       do{
+        if(stoll(s)>=n)
+        {
+            cout<<s<<endl;
+            return 0;
+        }
+       }while(next_permutation(s.begin(),s.end()));
+   }
+}
\ No newline at end of file
diff --git a/Codeforces/Codeforces_90_1373C.cpp b/Codeforces/Codeforces_90_1373C.cpp
new file mode 100644
index 0000000..93575d9
--- /dev/null
+++ b/Codeforces/Codeforces_90_1373C.cpp
@@ -0,0 +1,27 @@
+#include<bits/stdc++.h>
+using namespace std;
+int main()
+{
+	int n;
+	cin >> n;
+	for (int j = 0; j < n; ++j)
+	{
+		string s;
+		cin>>s;
+		long long int res=0,cur=0;
+		int flag=1;
+		for(int i=0;i<s.size();i++)
+		{
+			if(s[i]=='-')
+			{
+				cur-=1;
+				if(cur<0) {res+=i+1; cur+=1;}
+			}
+			else 
+			 cur+=1;
+		}
+		if(cur>=0) res+=s.size();
+		cout<<res<<endl;
+	}
+	return 0;
+}
\ No newline at end of file
diff --git a/Codeforces/proof_1373C.png b/Codeforces/proof_1373C.png
new file mode 100644
index 0000000..a7bfedd
Binary files /dev/null and b/Codeforces/proof_1373C.png differ
diff --git a/Codeforces/proof_777B.png b/Codeforces/proof_777B.png
new file mode 100644
index 0000000..fabc6d6
Binary files /dev/null and b/Codeforces/proof_777B.png differ
diff --git a/Codeforces/proof_96B.png b/Codeforces/proof_96B.png
new file mode 100644
index 0000000..5aaeafd
Binary files /dev/null and b/Codeforces/proof_96B.png differ