diff --git a/A/04/23/task01.c b/A/04/23/task01.c
new file mode 100644
index 000000000..52f6552d6
--- /dev/null
+++ b/A/04/23/task01.c
@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+int main(){
+	int n,a[100],i=0;
+	scanf("%d",&n);
+	while(i<n){
+		scanf("%d",&a[i]);
+		i++;
+	}
+	while(i>0){
+		i--;
+		printf("%d\n",a[i]);
+
+	}
+}
diff --git a/A/04/23/task02.c b/A/04/23/task02.c
new file mode 100644
index 000000000..bcdc3c23c
--- /dev/null
+++ b/A/04/23/task02.c
@@ -0,0 +1,19 @@
+#include <stdio.h>
+
+int main(){
+	int n,i=0,s,a[100],b;
+	scanf("%d",&n);
+	while(i<n){
+		scanf("%d",&b);
+		if(b%2!=0){a[i]=b;i++;}
+	}
+	n=n-1;
+	i=0;
+	while(i<n){
+		s=a[i]-a[n];
+		n--;
+		i++;
+		printf("%d\n",s);	
+	}
+	if(i==n)printf("%d",a[i]);
+}
diff --git a/A/04/23/task03.c b/A/04/23/task03.c
new file mode 100644
index 000000000..1351b7833
--- /dev/null
+++ b/A/04/23/task03.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(){
+	int i=0,c=0,d=0;
+	char n[1000],b='A',a='a';
+	fgets(n, 1000, stdin);
+	while(d<26){
+		while(n[i]!='\0'){
+			if(n[i]==a || n[i]==b)c++;
+			i++;
+		}
+		if(c!=0)printf("%c - %d\n",a,c);
+		i=0;
+		a++;
+		b++;
+		d++;
+		c=0;
+	}
+}
diff --git a/A/04/23/task04.c b/A/04/23/task04.c
new file mode 100644
index 000000000..85f4097f5
--- /dev/null
+++ b/A/04/23/task04.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(){
+	int b=0,d=0,i=0;
+	float c,n[64];
+	while(!feof(stdin)){
+		scanf("%f",&c);
+		while(b<=i){
+			if(n[b]==c){d=1;break;}
+			b++;
+		}
+		if(d==0){n[i]=c;i++;}
+		b=0;
+		d=0;
+	}
+	printf("%d",i);
+}