diff --git a/20201225/main.go b/20201225/main.go
new file mode 100644
index 0000000..1f223d2
--- /dev/null
+++ b/20201225/main.go
@@ -0,0 +1,73 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+func main() {
+	fmt.Println(strings.Trim("Bob hit a ball, the hit BALL flew far after it was hit.", ",."))
+}
+
+func maxCountWord(s, ban string) string {
+	s = strings.ToLower(s)
+	sb := strings.Builder{}
+	for _, cn := range s {
+		c := byte(cn)
+		if isAlphabet(c) || c == ' ' {
+			sb.WriteByte(c)
+		}
+	}
+	ws := strings.Split(sb.String(), " ")
+	m := make(map[string]int)
+	for _, w := range ws {
+		if w == ban {
+			continue
+		}
+		m[w]++
+	}
+	max := 0
+	w := ""
+	for k, v := range m {
+		if v > max {
+			max = v
+			w = k
+		}
+	}
+	return w
+}
+
+func maxCountWord2(s, ban string) string {
+	m := make(map[string]int)
+	s = strings.ToLower(s)
+	sb := strings.Builder{}
+	for _, cn := range s {
+		c := byte(cn)
+		if isAlphabet(c) {
+			sb.WriteByte(c)
+			continue
+		}
+		if c == ' ' {
+			word := sb.String()
+			if word != ban {
+				m[word]++
+			}
+			sb = strings.Builder{}
+			continue
+		}
+	}
+	max := 0
+	w := ""
+	for k, v := range m {
+		if v > max {
+			max = v
+			w = k
+		}
+	}
+	return w
+
+}
+
+func isAlphabet(c byte) bool {
+	return c >= 'a' && c <= 'z'
+}
diff --git a/20201225/main_test.go b/20201225/main_test.go
new file mode 100644
index 0000000..2164b8b
--- /dev/null
+++ b/20201225/main_test.go
@@ -0,0 +1,59 @@
+package main
+
+import "testing"
+
+func Test_maxCountWord(t *testing.T) {
+	type args struct {
+		s   string
+		ban string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			"test1",
+			args{
+				s:   "Bob hit a ball, the hit BALL flew far after it was hit.",
+				ban: "hit",
+			},
+			"ball",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := maxCountWord(tt.args.s, tt.args.ban); got != tt.want {
+				t.Errorf("maxCountWord() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_maxCountWord2(t *testing.T) {
+	type args struct {
+		s   string
+		ban string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			"test1",
+			args{
+				s:   "Bob hit a ball, the hit BALL flew far after it was hit.",
+				ban: "hit",
+			},
+			"ball",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := maxCountWord2(tt.args.s, tt.args.ban); got != tt.want {
+				t.Errorf("maxCountWord() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}