diff --git a/1ano/2semestre/poo/src/utils/DateYMD.java b/1ano/2semestre/poo/src/utils/DateYMD.java
new file mode 100644
index 0000000..65bb60f
--- /dev/null
+++ b/1ano/2semestre/poo/src/utils/DateYMD.java
@@ -0,0 +1,94 @@
+package utils;
+
+public class DateYMD {
+    private int day;
+    private int month;
+    private int year;
+
+    public DateYMD(int day, int month, int year) {
+        if (!validDate(day, month, year))
+            throw new IllegalArgumentException("Invalid date");
+        this.day = day;
+        this.month = month;
+        this.year = year;
+    }
+
+    public void set(int day, int month, int year) {
+        if (!validDate(day, month, year))
+            throw new IllegalArgumentException("Invalid date");
+        this.day = day;
+        this.month = month;
+        this.year = year;
+    }
+
+    public int[] get() {
+        return new int[]{this.day, this.month, this.year};
+    }
+
+    public int getDay() {
+        return day;
+    }
+
+    public int getMonth() {
+        return month;
+    }
+
+    public int getYear() {
+        return year;
+    }
+
+    public void increment() {
+        if (this.day < monthDays(this.month, this.year))
+            this.day++;
+        else if (this.month < 12) {
+            this.day = 1;
+            this.month++;
+        } else {
+            this.day = 1;
+            this.month = 1;
+            this.year++;
+        }
+    }
+
+    public void addDays(int days) {
+        for (int i = 0; i < days; i++)
+            this.increment();
+    }
+
+    public void decrement() {
+        if (this.day > 1)
+            this.day--;
+        else if (this.month > 1) {
+            this.day = monthDays(this.month - 1, this.year);
+            this.month--;
+        } else {
+            this.day = 31;
+            this.month = 12;
+            this.year--;
+        }
+    }
+
+    public String toString() {
+        return String.format("%04d-%02d-%02d", this.year, this.month, this.day);
+    }
+    static boolean validMonth(int month) {
+        return month >= 1 && month <= 12;
+    }
+
+    static int monthDays(int month, int year) {
+        if (!validMonth(month))
+            return -1;
+        int[] daysPerMonth = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+        if (month == 2 && isLeapYear(year))
+            return 29;
+        return daysPerMonth[month - 1];
+    }
+
+    static boolean isLeapYear(int year) {
+        return year % 100 == 0 ? year % 400 == 0 : year % 4 == 0;
+    }
+
+    static boolean validDate(int day, int month, int year) {
+        return day >= 1 && day <= monthDays(month, year);
+    }
+}
\ No newline at end of file